Between 2009 and 2023, by its own count, LG Household & Health Care sold more than 3.33 million bottles of one watery essence. That essence is the su:m37 Secret Essence. In May 2024 the company was still rebuilding it, releasing what it called the fourth generation.
su:m37 is a fermentation brand from top to bottom. Its gift-box serums and its cool summer gel creams are sold on fermentation too. That is a large promise. Most of the numbers attached to it come from LG H&H itself.
For readers in Australia and New Zealand the useful questions are narrower: which of its many lines deserve shelf space, how the textures behave in a humid February or an air-conditioned office, and who should leave the brand alone. The last one is quick to answer. Anyone who reacts to essential oils.
In short
su:m37 is LG Household & Health Care's fermentation-based skincare brand, launched in Korea in October 2007.
Its best-known product is the Secret Essence, a watery first-step essence that LG H&H has reformulated several times since 2009.
Start with the Secret Essence EX, add the Water-full gel cream for hot months, and patch-test first if you react to essential oils.
Where su:m37 sits in Korea
At home, su:m37 is sold in department stores. LG H&H, the company that also makes The History of Whoo, launched it in October 2007. Herald Economy reported that it was introduced as Korea's first naturally fermented cosmetics brand and reached 40 billion won in sales within a year. The parent company grew out of Lucky Chemical, founded in 1947 and the maker of Lucky Cream, and counts su:m37 among its high-end brands alongside The History of Whoo, O HUI and belif (Wikipedia).
When the fourth-generation Secret Essence arrived in May 2024, LG H&H released it through department stores, online and at Olive Young.
The brand also became something travellers carry home. In 2016 the Korea Herald reported that su:m37's duty-free sales had grown 187% in 2015, and that the brand was opening its first store in China, in Hangzhou.
The intended customer is not chasing a trend. LG H&H's 2024 announcement called the Secret Essence a first-step "slow-ageing" essence. That phrase tells you who the brand is talking to.
What the su:m37 Secret Essence is built on
Fermentation, by the brand's own account, and the name spells it out. Sum (숨) is the Korean word for breath. On the brand's Korean site, the colon stands for the waiting time of fermentation, and 37° for the temperature the brand considers best for fermentation and maturation.
What goes into the bottle has been described differently over the years. In 2015 and 2016, Korean newspapers reported that the Secret Essence was built on about 80 plants and a fermented ingredient the brand calls Cytosis. A 2015 renewal added ferulic acid. LG H&H said its natural fermentation research institute had developed a "Ferm Origin Process" that adds rhythms of light and sound to water, soil, temperature and air. By the 2024 fourth generation, the figure was 86 plants grown across the four seasons, with a new ingredient the company calls Cyto-ferm Activator and four ceramides.
The current Korean listing for the 100ml Secret Essence describes "Bio-Breath Science", the brand's own fermentation process, and says the essence holds 90% fermented extract. Its first two ingredients are a yeast ferment filtrate and a lactobacillus ferment.
None of this is independent proof that fermented plants outperform other ingredients. The striking figures in the 2024 launch, such as ceramides the company says are 20% finer and 2.2 times more plentiful than in the third generation, come from LG H&H's own announcement. Treat them as the brand's claims. Judge the products by texture, finish and how your skin looks after a month.
The lines worth knowing
For a first purchase, three of su:m37's lines matter: Secret, LosecSumma and Water-full. The brand is organised by line rather than by a single hero, and its Korean store groups them as LosecSumma, Secret, Fermentalift, Time Energy, Water-full, Micro-Active and Skin Saver.
The Secret Essence EX is the Secret bottle sold here. The current Korean Secret Essence is a watery first step, used morning and night after cleansing; its instructions suggest an amount about the size of a 500-won coin, smoothed over the face and patted in. The names around it have moved. Korean price news in 2023 named a 100ml Secret Essence EX, LG H&H's 2024 launch spoke of a fourth generation, and the brand's Korean store now lists a 100ml Secret Essence with neither label. LG H&H does not spell out how one name maps onto the next, so read the ingredient list on the carton rather than trusting a name in an old review.
Two smaller Secret products are easier ways in. The Secret Essence Mist is a fine spray the brand suggests using whenever skin feels dry, held about 20cm from the face. The Secret Multi Pad carries the essence's ingredients on a two-sided pad: the patterned side wipes over the face, and the smooth side can sit on one area for about five minutes.
LosecSumma is the line su:m37 dresses up, and in Korea it turns up in holiday gift sets. The LosecSumma Elixir Treatment, launched in 2021, is another clear, watery first-step essence. At launch LG H&H said it contained "Golden Elixir", inspired by a fermentation recipe of the Roman imperial court, and "Aura Enzyme" with white truffle. Buy it for the ritual and the packaging. In a routine it does the same job as the Secret Essence.
Water-full is the hydration line, and in Korea it has been a bestseller. Etoday reported in 2020 that it sold one item a minute and passed 200 billion won in sales the previous year. The report came ahead of a renewal that added a fermented ingredient inspired by a 600-year-old Korean technique. The line now includes the Water-full Marine Relief Gel Cream. Fermentalift and Time Energy round out the range with serums and creams named for firming and radiance.
How it wears in Australian heat
Texture is where su:m37 earns a place in a hot-climate routine. The Korean listing describes the Water-full Marine Relief Gel Cream as a cool gel meant for the last step of skincare, and lists a lactobacillus ferment, several forms of hyaluronic acid, a ceramide and panthenol among its ingredients.
That makes it the cream for a Brisbane January or the Darwin build-up, when anything rich sits on the skin and slides under a hat brim. A watery essence followed by a gel gives a thin, two-layer routine that leaves room for sunscreen. In Australia, that is the step that matters most.
Winter is a different job. From June to August, in a heated Melbourne office or on a frosty Canberra morning, an essence and a gel may feel too light by evening. Keep the essence and put something richer on top.
su:m37 makes sunscreen too. The Sun-away Cooling Watery Sun Block AD is SPF50+ PA+++ as labelled in Korea. Those ratings are measured to Korean, not Australian, standards, so apply it generously and reapply as you would any sunscreen in a summer when the UV index often passes 11.
Who should skip it
Anyone who reacts to fragrance or essential oils should go carefully. On su:m37's Korean store, the current ingredient list for the 100ml Secret Essence includes lemon peel, lavender, grapefruit peel and scented geranium oils, along with limonene, linalool and citronellol, fragrance components some people are sensitive to. The same listing tags the essence as low-irritation. The Water-full gel cream is no exception: its Korean list includes denatured alcohol and oils such as lime, bergamot and lavender. Natural and fermented still do not mean non-irritating for everyone.
Patch-test for a few days on the jawline before using it across the face, especially if your skin is already stressed by sun, wind or a strong active.
It is also not the brand for someone who shops by a single ingredient at a stated percentage. su:m37 builds long ingredient lists around its own named complexes, and its headline figures are its own. If you want to know exactly how much niacinamide is in the bottle, a single-ingredient serum will tell you more.
Where to start
Begin with the essence, because it is the product the brand has built and rebuilt since 2009, then add one product for your climate.
- Secret Essence EX: the brand's signature watery essence; use it after cleansing, morning and night, and judge it after a month.
- Water-full Marine Relief Gel Cream: a cool gel for humid summers and air-conditioned days that keeps the routine thin under sunscreen.
- Secret Multi Pad: a smaller step into the Secret line, with a patterned side for wiping and a smooth side for a five-minute rest on one area.
The Korean listings give the Secret Essence, the Multi Pad and the Water-full gel cream a shelf life of 36 months from manufacture. The Multi Pad box itself says the lot number and use-by date (YYYYMMDD) are printed below the QR code, so you can check them yourself. The box above reads C6A 20290503, a use-by date of 3 May 2029. What we send are the latest Korean editions, shipped direct from Korea.
